Learning From Errors

When recently making a clock, I learned a valuable lesson about using brass screws. It’s one of those old clocks that was hung in each classroom that school children used to watch wondering if the end of the school day would ever come. It has a pendulum and a large clock face with clearly printed numbers which teachers used to teach students how to tell time.

The one I’m was making had a brass basal which is mounted to the circular clock with small brass screws. I carefully turned the round timber clock on my lathe, and polished it to a brilliant shine using Ubeaut Shellawax. The dark reddish-brown River Redgum grain looked wonderful.

The basal is mounted with four screws, so I marked out the location for the pilot holes and drilled them with a bit just a fraction smaller than the screw’s thread. I was aware that soft brass screws are easily broken, so I took care in driving the screws home. At first, the screws went in easily, and I prided myself in the ease with which I was accomplishing the tricky task.

And then without any warning, the head of one of the screws simply turned off the shaft.

Wow! (That’s not exactly what I said at the time.)

Then I remembered reading that as the screw went deeper into the wood it faced more friction.

For the rest of the screws, I cut the thread in the wood with a steel screw of the same size and thread. Then I applied a candle wax to the brass screw to reduce friction and drove them all home with no further failures.